diff --git a/src/hwrenderer/scene/hw_decal.cpp b/src/hwrenderer/scene/hw_decal.cpp
index 5a3e509bfd..815032314f 100644
--- a/src/hwrenderer/scene/hw_decal.cpp
+++ b/src/hwrenderer/scene/hw_decal.cpp
@@ -95,7 +95,7 @@ void GLDecal::DrawDecal(HWDrawInfo *di, FRenderState &state)
 
 		for (unsigned k = 0; k < lightlist.Size(); k++)
 		{
-			secplane_t &lowplane = k == lightlist.Size() - 1 ? bottomplane : lightlist[k + 1].plane;
+			secplane_t &lowplane = k == lightlist.Size() - 1 ? frontsector->floorplane : lightlist[k + 1].plane;
 
 			float low1 = lowplane.ZatPoint(dv[1].x, dv[1].y);
 			float low2 = lowplane.ZatPoint(dv[2].x, dv[2].y);
@@ -404,7 +404,7 @@ void GLWall::ProcessDecal(HWDrawInfo *di, DBaseDecal *decal, const FVector3 &nor
 
 	gldecal->alpha = decal->Alpha;
 	gldecal->zcenter = zpos - decalheight * 0.5f;
-	gldecal->bottomplane = bottomplane;
+	gldecal->frontsector = frontsector;
 	gldecal->Normal = normal;
 	gldecal->lightlist = lightlist;
 	memcpy(gldecal->dv, dv, sizeof(dv));
diff --git a/src/hwrenderer/scene/hw_drawstructs.h b/src/hwrenderer/scene/hw_drawstructs.h
index 35a6d340e3..d500e67957 100644
--- a/src/hwrenderer/scene/hw_drawstructs.h
+++ b/src/hwrenderer/scene/hw_drawstructs.h
@@ -186,7 +186,6 @@ public:
 	};
 
 
-	secplane_t topplane, bottomplane;	// we need to save these to pass them to the shader for calculating glows.
 
 	// these are not the same as ytop and ybottom!!!
 	float zceil[2];
@@ -198,6 +197,7 @@ public:
 public:
 	seg_t * seg;			// this gives the easiest access to all other structs involved
 	subsector_t * sub;		// For polyobjects
+	sector_t *frontsector, *backsector;
 //private:
 
 	void PutWall(HWDrawInfo *di, bool translucent);
@@ -411,7 +411,7 @@ struct GLDecal
 	int rellight;
 	float alpha;
 	FColormap Colormap;
-	secplane_t bottomplane;
+	sector_t *frontsector;
 	FVector3 Normal;
 
 	void DrawDecal(HWDrawInfo *di, FRenderState &state);
diff --git a/src/hwrenderer/scene/hw_walls.cpp b/src/hwrenderer/scene/hw_walls.cpp
index b91c38ae1a..f8455c2459 100644
--- a/src/hwrenderer/scene/hw_walls.cpp
+++ b/src/hwrenderer/scene/hw_walls.cpp
@@ -140,7 +140,7 @@ void GLWall::RenderTexturedWall(HWDrawInfo *di, FRenderState &state, int rflags)
 		state.EnableGlow(true);
 		state.SetGlowParams(topglowcolor, bottomglowcolor);
 	}
-	state.SetGlowPlanes(topplane, bottomplane);
+	state.SetGlowPlanes(frontsector->ceilingplane, frontsector->floorplane);
 	state.SetMaterial(gltexture, flags & 3, 0, -1);
 
 	if (type == RENDERWALL_M2SNF)
@@ -167,7 +167,7 @@ void GLWall::RenderTexturedWall(HWDrawInfo *di, FRenderState &state, int rflags)
 
 		for (unsigned i = 0; i < lightlist->Size(); i++)
 		{
-			secplane_t &lowplane = i == (*lightlist).Size() - 1 ? bottomplane : (*lightlist)[i + 1].plane;
+			secplane_t &lowplane = i == (*lightlist).Size() - 1 ? frontsector->floorplane : (*lightlist)[i + 1].plane;
 			// this must use the exact same calculation method as GLWall::Process etc.
 			float low1 = lowplane.ZatPoint(vertexes[0]);
 			float low2 = lowplane.ZatPoint(vertexes[1]);
@@ -1799,6 +1799,8 @@ void GLWall::Process(HWDrawInfo *di, seg_t *seg, sector_t * frontsector, sector_
 	// note: we always have a valid sidedef and linedef reference when getting here.
 
 	this->seg = seg;
+	this->frontsector = frontsector;
+	this->backsector = backsector;
 	vertindex = 0;
 	vertcount = 0;
 
@@ -1893,8 +1895,6 @@ void GLWall::Process(HWDrawInfo *di, seg_t *seg, sector_t * frontsector, sector_
 
 
 	if (frontsector->GetWallGlow(topglowcolor, bottomglowcolor)) flags |= GLWF_GLOW;
-	topplane = frontsector->ceilingplane;
-	bottomplane = frontsector->floorplane;
 
 	zfloor[0] = ffh1 = segfront->floorplane.ZatPoint(v1);
 	zfloor[1] = ffh2 = segfront->floorplane.ZatPoint(v2);
@@ -2104,6 +2104,8 @@ void GLWall::ProcessLowerMiniseg(HWDrawInfo *di, seg_t *seg, sector_t * frontsec
 	if (bfh > ffh)
 	{
 		this->seg = seg;
+		this->frontsector = frontsector;
+		this->backsector = backsector;
 		this->sub = NULL;
 
 		vertex_t * v1 = seg->v1;
@@ -2129,8 +2131,6 @@ void GLWall::ProcessLowerMiniseg(HWDrawInfo *di, seg_t *seg, sector_t * frontsec
 		Colormap = frontsector->Colormap;
 
 		if (frontsector->GetWallGlow(topglowcolor, bottomglowcolor)) flags |= GLWF_GLOW;
-		topplane = frontsector->ceilingplane;
-		bottomplane = frontsector->floorplane;
 		dynlightindex = -1;
 
 		zfloor[0] = zfloor[1] = ffh;